HTML60秒倒计时

 1 <!DOCTYPE html>
 2 <html lang="en">
 3 
 4 <head>
 5     <meta charset="UTF-8">
 6     <title>60秒倒计时</title>
 7 </head>
 8 
 9 <body>
10     <input type="button" id="btn" value="获取验证码" onclick="sendemail()" />
11 </body>
12 
13 </html>
14 <script src="https://code.jquery.com/jquery-3.2.1.min.js"></script>
15 <script>
16 var countdown = 5
17 
18 function sendemail() {
19     var obj = $("#btn")
20     settime(obj)
21     console.log('发送邮件')
22 }
23 
24 function settime(obj) {
25     if (countdown == 0) {
26         obj.attr('disabled', false)
27         obj.val("获取验证码")
28         countdown = 5
29         return
30     } else {
31         obj.attr('disabled', true)
32         obj.val("重新发送(" + countdown + ")")
33         countdown--
34     }
35     setTimeout(function() {
36         settime(obj)
37     }, 1000)
38 }
39 </script>